Waitrose today made a commitment to supporting the growth of greener farming systems across the world, in the latest move by a supermarket to boast its environmental credentials.

The retailer pledged that by 2010 all conventional fresh, prepared and frozen fruit, vegetables and flowers on sale in is supermarkets would be farmed to high environmental standards using sustainable farming methods.

Organic produce will continue to be certified by the Soil Association, but all other items will carry the Leaf Marque.

In order to achieve LEAF Marque status, farms have to demonstrate high standards of environmental stewardship.

These include minimising use of pesticides, encouraging natural predators, retaining 'green corridors" to protect wildlife, conserving water and energy, and maintaining soil vitality through crop rotation.

Mary Vizoso, head of fruit and vegetable buying at Waitrose, said although some of the farming methods endorsed by the scheme were becoming well known in the UK, in developing countries they were often groundbreaking.

"This scheme will make an enormous difference to the long term future of farming communities," she said.

"Many communities in the developing world rely on trade in fruit and vegetables for their livelihoods.

"That is why we are working at grass roots level to raise environmental standards on farms and plantations around the world through widespread adoption of the Leaf marque scheme."

In the past 12 months the UK's grocers have announced a stream of initiatives designed to portray themselves as environmentally-friendly businesses with sustainable and green policies and a social conscience.

Consumers have become increasingly concerned about 'food miles' and the environmental impact of the food that they buy and eat.

Caroline Drummond, chief executive of Leaf, said she was delighted Waitrose had decided to adopted the scheme.

Ms Drummond said: "It sends out a very clear signal of Waitrose's commitment to responsible and sustainable agriculture right across the globe.

"Their farmer suppliers throughout the world will be recognised for producing food in harmony with the environment."